A. Field of the Invention
The present invention relates generally to the field of protein expression. More particularly, it concerns the transfer and expression of a gene of interest by the immune cells of an avian.
B. Description of Related Art
There is a growing interest in the use of domesticated species in the production of recombinant proteins. Large scale and commercial production of recombinant proteins generally employs either bacterial or yeast systems. There are, nevertheless, drawbacks to these systems. Agricultural species have been proposed as suitable systems for use in the production of high quality recombinant proteins. Agricultural species are readily available and advances in molecular biology have allowed engineering of these species for the large scale production of proteins of interest.
There is a major and continuing effort to exploit germ-line transgenic technology for the production of useful heterologous proteins at commercial scales in the milk of transgenic animals. Success has been achieved for some proteins up to a level, in a few cases, of about a gram/liter of milk (Yom et al., 1993). However, the germline transgenic approach for large animals, for example dairy cattle, is still under development and requires a major investment of both time and money to create a transgenic breading stock for each protein.
The use of poultry species as a source of high quality, relatively inexpensive recombinant protein is largely unexplored. While it has been hypothesized that chicken B-cells may be useful in the production of recombinant proteins, to date this goal remains unrealized in any practical sense. The ability of avian B-cells to secrete large quantities of immunoglobulin into the egg yolk has, however, been commercially exploited.
Several companies now offer kits for the production and purification of chicken immunoglobulin, IgY. Immunized hens are used to produce high quantities of purified polyclonal IgY (equivalent to mammalian IgG). Fifty to eight milligram quantities of immunoglobulin IgY can be purified from individual egg yolks using simple, rapid and convenient methods. The ability to isolate and purify IgY has yet to be explored as a means of producing and purifying recombinant material.
The instant invention sets forth processes and methods for the production isolation and purification of high quality recombinant proteins from avian species, specifically from lymphoid cells.